1. Field
One or more exemplary embodiments relate to an image pickup apparatus and method for generating an image having depth information, and more particularly, to an image pickup apparatus and method capable of improving the resolution of an image having depth information which is generated using light field technology.
2. Description of the Related Art
A related art two-dimensional (2D) camera generates an image by acquiring, via an image sensor, information on the intensity of light incident through an objective lens. For example, information on the intensity of light for one point of an object may be obtained by focusing a plurality of light beams from the one point of the object on one point of the image sensor through the objective lens and accumulating the intensity of light for a preset time. In this way, one image may be generated using information on the intensity of light that is obtained from a plurality of pixels of the image sensor. However, in an image pickup method of the 2D camera, information on intensities and directions of individual light beams coming from one point of an object cannot be acquired.
Light field technology is used to generate an image corresponding to an arbitrary viewpoint or an arbitrary focal point by acquiring information on individual intensities and directions of a plurality of light beams coming from one point of an object. When the light field technology is used, a three-dimensional (3D) camera capable of obtaining information on a plurality of viewpoints of an object and depth information of the object may be implemented. Additionally, a camera having a refocusing effect capable of focusing on all objects within a view angle may be implemented.
A camera to which the light field technology is applied may be implemented by using a main lens and a micro lens array. For example, the micro lens array having a plurality of 2D-arranged micro lenses may be arranged between the main lens and an image sensor. One micro lens in the micro lens array may correspond to a plurality of pixels in the image sensor. Therefore, images of different viewpoints may be respectively obtained from the plurality of pixels corresponding to the one micro lens. For example, when the one micro lens covers 7×7 pixels, 49 (i.e., 7×7) images of different viewpoints may be simultaneously obtained.
However, the resolution of an image in a light field camera is determined not by a pixel pitch of an image sensor, but by a pitch of a micro lens. For example, an increase in the size of a micro lens causes a decrease in the resolution of an image, and a decrease in the size of a micro lens causes an increase in the resolution of an image. Therefore, when the size of a micro lens increases in order to increase the number of images having different viewpoints (i.e., the number of pixels corresponding to the micro lens), the resolution of an image decreases. Conversely, when the size of a micro lens decreases in order to increase the resolution of an image, the number of simultaneously obtained images having different viewpoints decreases. As a result, a trade-off occurs between the resolution of an image and a parallax detection ability.